Research On Key Techniques Of Image Encryption Based On Chaos

In recent years,with the rapid development of multimedia and network technology,the security of image data security has attracted much attention,and the protection of image data information has become a hot research topic.The study found that the chaotic characteristic is very suitable for image data protection.The good characteristics of chaos theory will play an important role and it is very practical.Compared with traditional encryption technology,chaotic image encryption technology has many advantages,such as better encryption effect and higher security.Therefore,the research on the key technology of image encryption based on chaos has high theoretical and practical significance.This thesis studies and analyzes the mainstream chaos theory,attempts to apply these chaotic theories to the field of image encryption,and proposes the corresponding image encryption scheme based on these chaotic theories.In order to process image encryption information more efficiently,the schemes of image encryption preview are also studied in this thesis.The main contents of this thesis are summarized as follows:1.Based on the excellent properties of chaotic tent map,a novel image encryption scheme is proposed.The main design idea of the scheme is: Firstly,the chaotic key stream used for image encryption is generated by combining the chaotic characteristics of chaotic tent map with the original image data.Secondly,the chaotic key stream generated by one-dimensional chaotic tent map is used to encrypt the image.Finally,the simulation experiment and general security analysis are used to verify the performance of the proposed image encryption.Experimental simulation and security analysis results show that the proposed scheme has good encryption effect,high speed and high security.2.Based on the chaotic properties of Logistic maps,this thesis extend the one-dimensional Logistic map to three dimensions and propose an image encryption scheme based on 3D Logistic chaotic map.Firstly,the 3D Logistic chaotic map is improved to generate the key stream.Secondly,the chaotic key stream is generated by using 3D Logistic chaotic mapping,and it has better randomness and security.It provides the necessary properties for secure image encryption schemes,including obfuscation and diffusion characteristics.The security and performance analysis of the proposed image encryption scheme is performed using the well known method.Simulation experiment results and security analysis show that the proposed scheme is effective and secure,and satisfies the requirements of image encryption for large key space,high security and high encryption efficiency.These excellent features make it suitable for image encryption applications.3.Another novel image encryption scheme is proposed based on the chaotic skew tent map and the Arnold transform to solve the problem of the small key space of image encryption using the Arnold transform,The scheme firstly generates the key according to the plaintext,then uses chaotic skew tent map and Arnold transform to diffusion and confusion the image data.This scheme introduces the idea of using double chaotic map to encrypt,which greatly increases the key space,makes the ciphertext randomness,more offensive resistance and ensures the encrypted ciphertext image more secure.Security analysis and experimental simulation show that the proposed scheme can encrypt images more efficient,and can effectively prevent all kinds of attacks against encrypted images.4.Aiming at solving the problem of low encryption efficiency of traditional chaotic image encryption schemes,this thesis propose a parallel image encryption scheme based on chaotic Duffing oscillator and parallel computing technology.Compared to text data,image data has greater amount of data and stronger relevance,which leads to slower image data encryption than text encryption.In order to improve the practical value of image encryption,the encryption efficiency must be improved so that the encryption and decryption time can be reduced to an acceptable level.The research on improving encryption efficiency and ensuring security has become the core issue of information security researchers.Applying parallel computing technology to the field of chaotic image encryption can make image encryption faster and faster on the basis of security.After studying the chaotic characteristics and parallel computing techniques of Duffing oscillators,a solution for image encryption using chaotic mapping and parallel computing is proposed.The simulation experiment results show that the encryption and decryption speed has been greatly improved.And the security analysis shows that the scheme meets the security requirements of image encryption,and has high practicability.5.Aiming at solving the problem of how to find the needed image quickly when there are many encrypted images,a scheme based on the preview of encrypted digital images is proposed.In order to realize digital image encryption preview,it is necessary to solve the problem of how to extract key preview information.This thesis can compress or reduce our image as a preview image,or extract one or more key information areas from original image as our preview image.Based on this idea,this thesis carried out a detailed design and proposed an encrypted digital image preview scheme based on a novel image encryption algorithm.And this thesis presents the design and implementation of the scheme in detail.To the best of our knowledge,this work is the first attempt to propose such a scheme in the area of image encryption.Security analysis and simulation experience results show that the scheme can decrypt the encryted preview image before the encrypted initial image was decrypted.Then this thesis can decide whether or not to continue the full digital image decryption operation according to the preview image is needed or not.The greatest advantage of the proposed algorithm is that it saves a lot of unnecessary decryption time.The comparison experiment shows that the scheme can preview the encrypted digital image with good effect,high efficiency and wide application prospect.